I installed Vista last night and got it all up and running with the latest ATI drivers. I started with one card and once I had the drivers installed then added the 2nd 3870. Everything ran great in crossfire till I added the 3rd 3870, and when I went to start it back up it would not boot into windows.
I shut it down and removed the 3rd card but the damage was already done and ended up reinstalling Vista.
I have installed Vista 4 more times today trying to get Tri-Fire working, but it just keeps killing windows on boot.

ok, hold on for a sec... "kills windows"?
that sound a bit wierd... to be honest its not sounding possible... i mean windows is an operating system on your harddrive that will not / can not be affected by a graphic card installation before it boots up fresh from the disk...

worst case scenario, your PSU is not giving them enough juice and you get a black screen... but for vista to not boot, i find that unlikely... and if that were the case, on the next boot you could boot on one card in safe mode....

To have to reinstall windows just in order to see the screen again becuase of vista is not the problem.

Perhaps describe what actually happens... like you boot windows... you get a blank screen... or you get graphical corruption on boot... or the monitor lights blink and the lcd panel says "no signal"... either way i seriously doubt your windows installation is going to get messed up becuase you installed another card... bios just wont do that to an operating system on boot.

I tried a 3870X2, my friends, and both of my 3870's not to long ago. I could get the X2 to work with one 3870 for about 5min til the system crashed and with all of the cards in my system no go. Recently found my PSU is bad so I'll try again when I get a working one back.

Wow, your problems are incredible. I ran a system with 2 3870s, 3 3870s, a 3870x2 & 3870, & 2 3870x2s. The only problems I've had was the GD cat install mess but I was always able to install the cards right after countless times. I got it down to a science now. They really need to fix that BS soon.

The troublesome install can destabilize some systems that aren't completely stable to begin with. I do have a friend that blew one of his HDs after he had to restart his system over 200 times by trying to install 2 3870s. He finally called me after his system wouldn't boot up anymore. I got him a new HD & installed his 2 3870s & cat in 10 minutes. You couldn't imagine the look he gave me

all ways remember one thing Bytor. Whenever your trying out new hardware, ocing your computer or video card, and anything else, its all ways trial and error... It can be pain full and take up all your time... but if you can't just keep at it.. then its better to keep everything stock.. IMO that is

Hey Bytor,
Your problem does sound like lack of power to the cards, can you boot to safe mode? if so do all three cards show in device manager and show the correct driver under properties?...You may also need to run more power direct to your pce bus...on enthusiast boards there is often a 4-pin molex connector for this purpose, also maybe try going into your bios and increasing the frequency of your pcie bus (just a bit!)...iether way i hope you get this sorted with minimum hassle.
Cheers, Craig0

It won't let me boot into anything windows when I have all 3 cards installed. Just goes to a Resume windows things and thats as far as it gets.
I purchased the 3rd card just for this reason, but now may not have a use for it.

Antec NeoHe 550-manufactured by seasonic -replacement to the discontinued smart power series

Software:

Windows XP pro SP2 -- vista is still crap

thats a lot of accessories! have you tried removing some of those and trying the 3rd card? also what is your psu brand, im guessing its not one of the real good ones and its probably no where near 750w of power output during regular operation.

Its the PSU... I didn't want to mess up my install on the 640 gig HDD so I pulled one of my Raptors out of the closet and installed Vista on it just to test the PSU issue on.
It worked best with all 3 cards installed from the start then install the drivers.